28779109 has 2 divisors, whose sum is σ = 28779110. Its totient is φ = 28779108.

The previous prime is 28779103. The next prime is 28779137. The reversal of 28779109 is 90197782.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27562500 + 1216609 = 5250^2 + 1103^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28779109 is a prime.

It is a super-2 number, since 2×28779109² = 1656474229667762, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28779103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14389554 + 14389555.

It is an arithmetic number, because the mean of its divisors is an integer number (14389555).

Almost surely, 2^28779109 is an apocalyptic number.

It is an amenable number.

28779109 is a deficient number, since it is larger than the sum of its proper divisors (1).

28779109 is an equidigital number, since it uses as much as digits as its factorization.

28779109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63504, while the sum is 43.

The square root of 28779109 is about 5364.6163888949. The cubic root of 28779109 is about 306.4496394260.

The spelling of 28779109 in words is "twenty-eight million, seven hundred seventy-nine thousand, one hundred nine".